Enzymes · NEET PG Preparation Biochemistry

A patient is treated with a specific pharmacological inhibitor that binds reversibly to the active site of a target enzyme, preventing substrate bind…

Practice question from Enzymes (NEET PG Preparation Biochemistry), with the correct answer and a step-by-step solution.

medium · MCQ · Q-F795A1

A patient is treated with a specific pharmacological inhibitor that binds reversibly to the active site of a target enzyme, preventing substrate binding. On a Lineweaver-Burk plot, how do the kinetic parameters VmaxV_{max} and apparent KmK_m change in the presence of this inhibitor?

  1. A.Vmax decreases, apparent Km remains unchanged
  2. B.Vmax remains unchanged, apparent Km increasesCorrect answer
  3. C.Both Vmax and apparent Km decrease
  4. D.Vmax remains unchanged, apparent Km decreases

Solution

This describes competitive inhibition. A competitive inhibitor binds reversibly to the active site, competing with the substrate. Because high substrate concentrations can overcome the inhibition, VmaxV_{max} remains unchanged. However, more substrate is required to reach half-maximal velocity, resulting in an increased apparent KmK_m.

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